German Patent Publication DE 41 15 092 A1 describes the mounting of electromagnetic switching devices on printed circuit boards. To this end, the switching device is provided on the back with soldering pins which are inserted into corresponding holes and then soldered to contacting conductor surfaces of the printed circuit board. The disadvantage is that in the event of a failure of the switching device, the failed device can be replaced with a new one only with great effort and with the risk of damaging the printed circuit board or the switching device. Another disadvantage is that, for conventional wiring on the one hand, and, on the other hand, for connection to printed circuit boards, switching devices that are suitable for the respective connection method have to be provided separately.
European Patent Publication EP 0 779 640 A2 discloses a combination of an electromagnetic switching device and a bus-compatible amplifier module. The switching device is provided with connecting terminals and coil terminals on the connection sides running perpendicular to the front of the switching device. The connecting terminals are connected inside the device to switchable conducting paths, i.e., to power and auxiliary contacts, via connecting conductors. The amplifier module has connector pins which are connectable to the coil terminals leading to the operating coil of the switching device. This combination does not provide for the connection of the amplifier module to the switchable conducting paths via the pin contacts. World Patent Publication WO 81/01092 A1 describes a switching device having an integrated printed circuit board which is connected via pin contacts to a further printed circuit board inside the switching devices.